Circuit board connector

ABSTRACT

The invention generally relates to a connector ( 1 ) for receiving a cable end ( 12 ), arranged for being attached to a circuit board. The connector is provided with a through hole ( 10 ) for receiving the cable end, at least one upper lip ( 5 ) and at least one lower lip ( 3 ) with a connector recess ( 11, 13 ) therebetween for fitting onto an edge of a slit ( 6 ) in the circuit board. The connector is further provided with at least one snap holding element ( 4 ), disposed adjacent to said connector recess ( 11, 13 ), so as to engage with a portion ( 7 ) of the circuit board, adja-cent to the edge of the slit  6  in the circuit board.

FIELD OF THE INVENTION

[0001] The present invention relates to a circuit board connectoraccording to the introductory portion of claim 1. It further relates toa circuit board with a circuit board connector according to claim 10.Specifically, the invention concerns a circuit board connector forreceiving a cable end, and arranged for being attached to a circuitboard.

BACKGROUND OF THE INVENTION

[0002] A number of circuit board connectors for receiving a cable end,such as a coaxial cable, and arranged for being attached to a circuitboard and electrically connecting the cable to the circuit boardcomponents, are available. Such a connector is intended for holding thefree end of a cable conductor, such that it is not detachable from theconnector while still relieving the free cable conductor end ofmechanical stress, and electrically connecting the cable conductor tothe circuit board. The connectors may have further purposes, such aselectrically shielding the free cable conductor end, and fixing the waveguiding properties of the connection between the free cable conductorand the circuit board by a well defined geometry of the connector.

[0003] A particular difficulty in achieving electrical properties thatare consistent for a series of connector units, is fixing the positionof the connector with a large degree of accuracy. Small shifts in theposition of the connector and of the electrical conductor, which isconnected, to the circuit board, particularly in the general directionof the cable end, will cause comparatively large changes in theelectrical properties. This sensitivity to small position changesincreases with increasing frequency, and the sensitivity is very largein the microwave region.

[0004] Often, this is solved by inserting the connector terminals intosnugly fit through holes on the circuit board. The terminals are thenattached to the circuit board by soldering. This has the disadvantagethat the connector is partially held in place by way of soldering.

SUMMARY OF THE INVENTION

[0005] A general object of the invention is to provide a circuit boardconnector, which solves the problem, discussed above and which can beattached to the circuit board with a large degree of positioningaccuracy, and be held in place without soldering.

[0006] This object is attained with a circuit board connector having thefeatures of claim 1.

[0007] Accordingly, the invention generally relates to a connector forreceiving a cable end arranged for being attached to a circuit board.The connector is provided with a through hole for receiving the cableend, at least one upper lip and at least one lower lip with a connectorrecess therebetween for fitting onto an edge of a slit in said circuitboard. The connector is further provided with at least one snap holdingelement disposed adjacent to the connector recess so as to engage with aportion of the circuit board, adjacent to said edge of said slit in thecircuit board.

[0008] According to another aspect of the invention, the connector iselectrically conducting, and thus establishes an electrical connectionbetween the cable shield and the lower side of the circuit board throughthe lower lip. This is particularly advantageous if the ground plane ofthe circuit board is located on the lower side of the circuit board.

[0009] The invention will now be explained further below with referenceto the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 shows the rear face and the side of a connector accordingto the invention.

[0011]FIG. 2 shows the front face and the side of a connector accordingto the invention.

[0012]FIG. 3 shows a connector according to the invention in a sideview.

[0013]FIG. 4 shows the outline of through holes in a circuit board forreceiving a connector according to the invention.

[0014]FIG. 5 shows a circuit board from below, where the through holesare receiving a connector according to the invention.

[0015]FIG. 6 shows a circuit board from below, with a connectoraccording to the invention in a locked position.

[0016]FIG. 7 shows a side view of a connector according to the inventionon a circuit board.

[0017]FIG. 8 shows a perspective view of the connector of FIG. 7 on acircuit board.

[0018]FIG. 9 shows the connector of FIG. 7 on the circuit board in a topview.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0019]FIGS. 1-3 show close-up views of a connector 1 according to theinvention, from three different angles. The connector comprises a hole10 extending through a connector body 2 for receiving a cable end. Uponassembly, the shield of the cable is electrically connected to the body2 by soldering into a slot 14. The body 2 is provided with two upperlips 5 and a lower lip 3, which extend sideways and forwards from thebody respectively. These lips 5, 3 are situated on the upper side andthe lower side of a circuit board, respectively, when the connector isattached to the circuit board (FIGS. 7-9). Between the upper and lowerlips there is a recess 11, 13, which is designed to precisely fit ontothe edge of a slit 6 in the circuit board, so that the lips 5, 3 holdthe connector 1 on the circuit board and prevent translational movementsin the vertical direction.

[0020] In the embodiment shown, the upper lips 5 are located at alongitudinal distance from the lower lip 3. However, alternatively theupper lips 5 may be placed immediately above the lower lip 3, and thusbe directly separated by the recess 11.

[0021] The recess 11 is designed to allow the connector to slidelongitudinally forwards into the slit 6 of the circuit board as far asthe slit extends. Sideways movement of the connector is prevented by thewidth of the slit 6. According to the invention, the connector 1 alsohas two snap holding elements 4 extending sideways from the body atessentially the same height as the lower lip 3. In conjunction with thelips 5 and the lower lip 3, the elements 4 hold the connector in placeon the circuit board, when positioned in its final, locking position.The snap holding elements 4 will force the circuit board to bend upwardssomewhat as the connector is inserted into the circuit board slit, andupon pushing the connector forwards into its final position, the snapholding elements 4 will snap into corresponding holes 7 through thecircuit board, these holes 7 serving as locking portions. The frontsurface 13 of the recess 11 prevents the connector from sliding forwardsfurther, while the snap holding elements 4 prevent the connector fromsliding backwards.

[0022] The engagement of the connector with the locking portion 7 ismore clearly illustrated in FIGS. 4-6. FIG. 4 shows the outline of theslit 6 in the circuit board, and the locking portions 7. The slit 6 isdesigned to receive the lower lip 3, and is provided with sideextensions 6 a, 6 b for receiving the snap holding elements 4. FIG. 5shows the slit 6 from the lower side of the circuit board, where theconnector has been inserted into the slit, but not yet been pushed intoits locked position. In FIG. 6, the connector, upon being inserted intothe slit, has been pushed forward into its locked position, where thesnap holding elements 4 engage into the holes 7, and the front surface13 of the recess 11 abuts against the inner edge portion of the slit 6.The through holes 7 and the slit 6 may be fabricated by drilling usingdrill steels of two different diameters, or alternatively by milling.

[0023]FIGS. 7-9 show three views of a connector in its locked positionon the circuit board with the cable mounted in the connector, from threedifferent angles. The connector is held in place by its engagement withthe slit 6 and the through holes 7, with minimal play. The innerconductor 8 of the cable extends forwardly towards a microstripconductor 9, and is held in place by the connector 1. The shield of thecable is in direct electrical contact with the conducting connector, andis thereby in electrical contact with the lower lip 3. The innerconductor 8 of the cable may now be soldered to the microstrip conductor9, and the lower lip 3 and the snap holding elements are soldered to aground plane on the lower side of the circuit board. The solder is notmechanically stressed if the connector is exposed to a force by, forexample, the cable being pulled in a direction from the circuit board.Instead, the forces are received by the circuit board itself.

[0024] As shown in FIG. 8, the insulating core 15 of the cable (e.g.made of Teflon) extends somewhat outside the hole 10 to maintain asecure isolation distance between the shield and the inner conductor ofthe cable.

[0025] In FIGS. 4-6 and 8-9, the slit 6 is shown as an essentiallyT-shaped through hole in the circuit board and the locking portions 7,are shown as round through holes in the circuit board, but these mayalternatively be differently shaped, as long as they receive, hold andlock the connector on the circuit board. One such alternative embodimentis a slit 6, which extends directly from a straight edge of the circuitboard, where the wider portion of the slit 6 a, 6 b (the top bar in the“T”) is lacking.

[0026] As shown in FIG. 5, the wider portion 6 a, 6 b receives theconnector when being inserted from above. The locking portions 7 mayalternatively be embodied as recesses instead of through holes, they mayextend from the slit instead of being separate, or they may be embodiedas hooks extending somewhat into the slit co-operating withcorrespondingly designed snap holding elements 4.

[0027] An advantage of using a conducting connector according to theinvention is the relatively large surface of the connector along whichthe ground current is conducted in a well defined way with low currentdensity from the shield of the cable, via the connector to the groundplane of the circuit board. In this way low intermodulation effects willbe obtained. The high frequency ground current from the cable shield mayeasily flow from the whole circumference of the shield to the lower lip.A further advantage of the illustrated embodiment is its low height uponassembly.

[0028] The connector according to the invention may be manufactured byfor example casting of zinc or some other metal or alloy. Surfacecoating with for example copper and silver will enhance the electricalproperties further, in particular with regard to low intermodulationlevels.

1. A connector (1) for receiving a cable end (12), and arranged forbeing attached to a circuit board, said connector being provided with athrough hole (10) for receiving said cable end, at least one upper lip(5) and at least one lower lip (3) with a connector recess (11, 13)therebetween for fitting onto an edge of a slit (6) in said circuitboard, characterised in that the connector is further provided with atleast one snap holding element (4), disposed adjacent to said connectorrecess (11, 13), so as to engage with a portion (7) of the circuitboard, adjacent to said edge of said slit (6) in the circuit board. 2.The connector according to claim 1, characterised in that said connectorrecess (11, 13) is arranged to receive said slit edge in a longitudinaldirection being essentially parallel to the direction of the centre axisof said through hole (10), said recess 11 having a front surface 13abutting against said edge.
 3. The connector according to any one ofclaims 1-2, characterised in that said snap holding element (4) isarranged to lockingly engage with said portion (7), such that saidconnector is prevented from moving in the direction along which saidrecess receives said slit edge.
 4. The connector according to any one ofclaims 1-3, characterised in that the interior surface of said throughhole (10) is electrically connected to said upper and lower lips (5, 3).5. The connector according to claim 4, characterised in that said lowerlip (3) is adapted to electrically contact a ground plane on the lowerside of said circuit board.
 6. The connector according to any one ofclaims 1-5, characterised in that said snap holding element (4) isarranged on the lower side of said connector recess (11, 13).
 7. Theconnector according to any one of claims 1-6, characterised in that itis provided with two snap holding elements (4), which extend outwardlysideways.
 8. The connector according to any one of claims 1-7,characterised in that each snap holding element (4) is arranged to fitinto a recess (7) forming said circuit board portion.
 9. The connectoraccording to any one of claims 1-8, characterised in that the snapholding element(s) (4) and the lips (3, 5) are spaced from each otherlongitudinally.
 10. A combination of a circuit board and the connectoraccording to any one of claims 1-9, characterised in that said slit (6)in the circuit board is an essentially T-shaped hole (6 a, 6 b).